Require Chef 13+ as a dev dep (#441)
Require Chef 13+ as a dev dep (#441)

Chef 11 is beyond EOL at this point

Signed-off-by: Tim Smith <764ef62106582a09ed09dfa0b6bff7c05fd7d1e4@chef.io>
swalberg/knife-vsphere,swalberg/knife-vsphere,ezrapagel/knife-vsphere,chef-partners/knife-vsphere,adamleff/knife-vsphere